The electric-field induced metallization of correlated insulators is a powerful means of creating novel electronic phases but requires high electric fields often beyond those achievable by conventional dielectric gates (1-3). Such fields can be achieved at interfaces using Schottky junctions (4) or polar materials (5, 6) or at surfaces by using ionic liquids (ILs) (7) as the gate dielectric in field effect transistor devices (8-10). The latter method allows for tunable electric fields without restriction on the channel material or its crystal orientation. One of the most interesting and widely studied materials is the correlated insulator VO2 (11, 12) which exhibits a metal to insulator phase transition (MIT) as the temperature is reduced below ˜340 K in bulk material (13). Recently, electrolyte gating has been shown to dramatically alter the properties of thin films of VO2, in particular, the metallization of the insulating state was achieved and attributed to the introduction of small numbers of carriers that are electrostatically induced by the gating process (14). This would be consistent with the destabilization of a Mott insulating state in VO2 that depends critically on electronic band half-filling, which has been a long-standing goal in condensed matter physics (15).